ode to operate at room temperature. Scientists have discovered a new material that allows an ultrafast electron diode to function at room temperature. The electron diode is a fundamental component of modern electronics and is essential for converting alternating current into direct current. Previously, such diodes could only operate at extremely low temperatures. The researchers achieved this breakthrough by adding a layer of the new material to the diode, which allowed it to function efficiently at room temperature. This discovery could pave the way for the development of faster and more energy-efficient electronics in the future..
Article Highlight | 8-Sep-2023
Bright electron beams unlock the study of small, thin materials on ultrafast timescales.
image: The new ultrafast electron probe apparatus is 3 meters long (left). The diffraction pattern (top right) encodes detailed information on the positions of the atoms within a small sample flake (bottom right).
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Credit: Image courtesy of Cornell University
The Science
Quantum materials have a host of exotic electronic, magnetic, and optical properties that make them prime candidates for use in future computing and energy technologies. Their properties arise from a complex interaction of their electrons and atomic nuclei. Researchers can observe these interactions as they happen using short pulses of X-rays or electron beams. These pulses last less than a trillionth of a second. Using new materials that emits a narrow electron probe, researchers have developed an ultrafast electron beam technique to probe small, thin pieces of quantum materials with very high resolution.
The Impact
Scientists so far cannot create many newly emerging quantum materials as large crystals. Instead, these materials form crystals only one-tenth as wide as a human hair. This poses a challenge for researchers probing these materials using ultrafast electron beam accelerators, as electron beam quality often limits how small an area these beams can focus on. In this study, researchers used a specialized source of electrons to produce a substantial improvement in electron beam quality. This enables crisp images of samples only a few microns wide and of processes that take place in less than a trillionth of a second. This work could lead to a clearer image and understanding of how quantum materials function at atomic space and time scales.
Summary
These accelerators typically generate ultrafast electron pulses via a process called photoemission, wherein laser light knocks electrons out of a material, usually a simple metal like copper. If the laser pulse is short in duration, the emitted electron beam will also be short. One challenge with typical photoemission sources is that the electrons emitted do not all travel in the same direction. This spread in emission angle can ultimately limit researchers’ ability to focus the electron beam on a small spot.
In this work, researchers developed a photoemission-based electron accelerator with an advanced, in-house grown photoemission material that produces many electrons with a much smaller spread in emission angle. Using this source in conjunction with precise electron focusing optics, the researchers performed proof-of-principle ultrafast electron diffraction experiments which showed the ability to resolve subtle atomic details in samples as small as just a few microns in size.
Funding
This research was supported by the Department of Energy Office of Science, Basic Energy Sciences and by the National Science Foundation.
Researchers have developed an ultrafast electron beam technique that allows them to study small, thin pieces of quantum materials with high resolution. Quantum materials have unique properties that make them useful for future technologies, but they can only be created as small crystals. The new technique uses a specialized source of electrons to produce high-quality electron beams, enabling researchers to obtain crisp images of samples and processes that occur in less than a trillionth of a second. This advancement could lead to a better understanding of how quantum materials function at atomic scales. The research was supported by the Department of Energy and the National Science Foundation.
Hashtags: #material #enables #ultrafast #electron
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